Deep fat cooking entails the use of a considerable volume of cooking oil which is elevated to a certain temperature and thereafter receives food to be cooked by immersion, typically contained in a basket. Once cooked, the food is removed from the cooking oil by elevating the basket from the oil.
This type of cooking has been the subject of some criticism on at least two fronts: the first involves the potential use of oil having harmful, high saturated fat (cholesterol) levels, and the second involves the hygienic aspect of continued reuse of oil which has cooking impurities retained within the oil from the ongoing use of the cooking oil. Collectively, these two problems merge to form a third economic consideration: namely, the use of high-quality oil having low cholesterol versus the need for frequent replacement of the oil as it becomes contaminated by prior cooking impurities left behind during the cooking process.
The first problem, the saturated fat value of the oil, can be resolved, ideally, with the use of known, low cholesterol oils. However, these oils are more expensive. The economic constraints in providing a food product which is within reach of mass market consumers puts a practical limit on both the price to be paid for the oil and the frequency with which the oil is replaced as it becomes laden with cooking impurities.